gamefreak614 on "CONTACT FORM not sending messages from yahoo users"

I can't figure out what the problem is.
I am using XYZscripts' Contact Form, have also tried BWS Contact Forms, but both have the same issue. I am not receiving any contact form messages from anyone who's entered a yahoo return email address. I've sent myself test messages (using XYZScripts and BWS) using yahoo, hotmail, gmail, msn, mac, aol, edu...all went through except yahoo. Anyone else have this problem?